> There's absolutely no evidence of that on the article.

If you treat evidence as in the law of excluded middle, then yes. But if you are ready for a probabilistic evidence, then the article is a piece of evidence.

It chains Fermi Paradox, and our lack of knowledge how to do metallurgy in space. They both combined raise probability of impossibility of Von Neumann probes. It is not a proof that rules out Von Neumann probes, but it raises doubts about them.